Comment by Rucadi
Why are flakes such a deal-breaker? While not ideal, you can still tag your versions in the .nix file instead of the lockfile.
I even had to avoid flakes in a system I developed used by ~200 developers since it involved a non-nixos OS and it involved user secrets (Tokens etc...) So with flakes I had to keep track of the secrets (and was a pain point, since they obviously didn't have to push them into the git repo) but nix flakes doesn't handle well omitting files on git (it ignores them also on nix commands). In the end, the workarounds were too messy and had to drop flakes entirely.
As a new user, I learned flakes first, and the tie-in with git tags/branches and the corresponding cli ergonomics aren’t something I’d be able to give up.